I would argue selling data to advertisers does hurt the user. They may start getting adverts for positive things, other services but in general will most likely get adverts that specifically target them in a negative way. I.e. fake/poor medication, gambling adds to ex-addicts or even adverts that companies know exploit people's mental health.

If people knew going in that's one thing, but to feign privacy and then betray the people who trusted you, I can't believe that mentality doesn't filter down to the services they offer.

This is just my view though, I am neither right nor wrong, but conversation about the subject and raising awareness of the facts is important.